Acting as a tachykinin receptor antagonist, aprepitant is used as a drug for treating and preventing nausea and vomiting.
It has furthermore been suggested that tachykinin receptor antagonists have utility in the treatment of anxiety, depression, anxiety-related diseases, dysthymic disorders, chronic obstructive airways disease, hypersensitivity disorders, vasospastic diseases, fibrosing and collagen diseases (U.S. Pat. No. 5,719,147).
However, aprepitant is difficult to subject into formulation because of its low solubility, and thus research has been directed toward solutions to the problem.
For example, nanoparticles of aprepitant with improved bioavailability are made by wet milling in the presence of an anti-flocculant, and a formulation of the nanoparticles of aprepitant is sold (under the brand name of Emend) (U.S. Pat. Nos. 5,145,684 and 8,258,132).
However, such formulations of conventional techniques bear problems of process complexity, likelihood of contamination, concerns associated with poor drug stabilization, and low efficacy.
Meanwhile, a study on the in vivo pharmacokinetics of a drug without dietary influence needs the dissolution of the drug before meals (e.g., fasted state simulated gastrointestinal fluid with a pH of 4.0), however, nowhere has the dissolution of aprepitant in a fasted state simulated gastrointestinal fluid been found in previous studies.